Bleaching composition



Exam-Mtg 3,243,378 Patented Mar. 29, 1966 3243 378 of Mona Industries, Inc., and which is reported to be BLEACHING coMPosrnoN dihydmgen EDTA- Edwin I. Stoltz, Holyoke, and Robert R. Mercer, In,

South Hadley Falls, Mass., assignors to Lestoil Products, Inc., Holyoke, Mass., a corporation of Delaware No Drawing. Filed Apr. 11, 1962, Ser. No. 186,654

1 Claim. (Cl. 252-99) This invention relates to bleaching textile materials in aqueous mediums, and has for its object providing for improvement in the extent of bleaching or lightening of the material.

According to the invention, there is used as a composition for bleaching in aqueous medium, a material comprising a textile oxidizing agent, a chelate agent, and a The buffer compound can be any of the compounds known in the art for providing a pH in the range of about 7-11 in aqueous textile treating media. The phosphates are desirable and disodium phosphate (sodium phosphate dibasic, Merck Index, 7th ed., p. 954). Other phosphates which can be used are the glassy phosphates, i.e. sodium tetraphosphate, sodium hexametaphosphate. A pH about 7.5-8.5 is preferable and the disodium phosphate, sodium tetraphosphate and sodium hexametaphosphate are accordingly desirable. A pH of about 7.68.0 is best and disodium phosphate provides this pH. While material such as sodium carbamate and sodium sulfate can be used,

buffer for providing a pH of about 7-11 in the aqueous they give higher pH than is preferred, e.g. they give pH medium. of 95-105.

The use of such a composition provides improvement in Regarding relative proportions for the materials, the the bleaching. textile oxidizing agent is preferably present in major pro- The aqueous media used within the contemplation of portion, i.e. in excess of the amount of the chelating agent the invention are such aqueous media as are generally and in excess of the amount of the butter. The oxidizing used as a medium in which to bleach textiles. Thus, the agent can be about 50-90%, or better about 75-90%, and medium is composed of naturally occurring water or water about 85% is particularly well suited. containing minerals, and, in particular, cations of metals The chelating agent can be present in minor proporas commonly are present in water used as a medium for tions, i.e. less than the amount of oxidizing agent. A bleaching. The cations can be, for example, of iron, coppreferred proportion is from a fraction of a percent such per, calcium, magnesium, etc. as 0.05 to 5%, and about 1% is desirable. The optimum While the reason for the improvement realized accordamount will depend on the particular chelating agent used. ing to the invention is not surely known, it is noted that For EDTA and nitrilotriacetic acid compounds about 1% the chelating agent may possibly interact with cations presis desirable. The Monaquest Cu brand chelating agent of ent in the medium and in this way alter the environment 3 Mona Industries, Inc., is highly effective in relatively small for the bleach with the result that improvement in bleachamounts, e.g. about 0.1%. Larger amounts of chelating ing is realized. It is surprising that the use of a chelating agent than 5% can be used, e.g. up to 15% or even more, agent provides improvement in bleaching since, on the but this is generally undesirable because though slight imone hand, it seems that the presence of metal cations in provement in bleaching is realized by the use of larger the medium would catalyze the action of the textile oxiamounts, the improvement is not enough to justify the dizing agent, whereas, on the other hand, it would be precorresponding increase in cost. Also, with some chelatdicted that the chelating agent would interact with metal ing agents, caking occurs if a large amount, e.g. over 5%, cations to tie up the cations and render them unavailable is used. This tends to cause loss of bleaching power for for catalyzing the action of the textile oxidizing agent. the composition. Be this as it may, however, as set forth above, it has been As to the buffer, this can be present in minor proporfound that improvement is realized by utilization of the tions, i.e. less than the amount of oxidizing agent. It can chelating agent. be about 5-30%, and about 14% is desirable.

The oxidizing agent can be any oxidizing agent suitable The invention is further described in examples below. for bleachin textiles. It can be eroxide roxide t g P Pe EXAMPLES chlorine, or hypochlorite bleaching material. Preferably the oxidizing agent is a peroxide type material, e.g. sgd

um perborate, potassium persulfate. Of these mentioned materials, sodium perborate is preferred. Suitable peroxides are metal peroxides such as zinc peroxide, peracetic acids, organic peroxides, and hydrogen peroxide. Preferred groups in addition to sodium perborate and potassium persulfate are: sodium perborate, potassium persul fate and hydrogen peroxide; sodium perborate and hydrogen peroxide; and potassium persulfate and hydrogen peroxide. Mixtures of the oxidizing agents can, of course, be used.

The chelating agent can be any chelate effective to sequester metal cations. Preferred chelating agents are EDTA (ethylene diamine tetracetic acid), water soluble salts of EDTA, nitrilotriacetic aid, and water solu l salts of nitrilotriacetic an The various $0M saiis,"e'.. rn e c., of these acids are desirable. The salts are more soluble and so are more convenient to use. Of these materials nitrilotriacetic acid and its salts are best suited for the purposes of the invention, and the nitrilotriacetic acid tri-sodium salt is desirable. EDTA is highly effective, particularly the EDTA disodium salt. Other chelating agents which can be used are Versimine Flake brand chelating agent of Dow Chemical Company and which is reported to be disodium salt of hydroxyethyliminodiacetic acid; Chel brand chelating agents, of Geigy Chemical Corp., and Monaquest Cu chelating agent In these examples a Launderometer of the American Association of Textile Chemists and Colorists was used. Desized and boiled off greige goods (unbleached cotton) in the form of 9" x 7" swatches was subjected to a series of washings; each washing was 20 minutes at 140 F., the concentration of the compositions of the invention in media used in the tests was 0.27 g./600 ml. water. Further, said media contained 0.91 g./ 600 ml. of Tide brand synthetic detergent. Washings using Tide brand synthetic detergent in amount of 0.91 g./ 600 ml. water were used as the control. The extent of bleaching was measured with a Hunter Reflectometer (D-40), taking 4B3G as the measure of whiteness, and the results are reported in percent of whiteness based on the whiteness for the control as 100%. The water used was tap water, and one series of washings was with water only.

The compositions were sodium perborate, and the remaining 15 was composed of disodium phosphate and cheating agent. The sodium perborate was the tetrahydrate; the disodium phosphate was anhydrous. (The per centages, however, are on an anhydrous basis.) The identity and amount of cheating agent is set forth with the tabulation of results which follows. In the tabulation, NTA means nitrilotriacetate trisodium salt and the numeral following the term EDTA indicates the sodium salt, 2, 3, and 4, indicating respectively, the di-, tri-, and tetrasodium salt.

Percent bleaching Percent Washing Example Chelating Chelating agent agent I II III 1V V VI VII NIA... 1 103. 7 133.0 125. 9 142. s 145. 1 154. s 147. s

NTA 14 103. 7 12210 115. 2 126. 2 128.0 120. 7 119. 5

EDTA4 1 103 128. 3 119. 5 135. 9 137. 3 145. 5 137. 1

EDTA-4 14 114. s 130. s 120. 0 131. 0 135. 3 131. 9 131. 5

EDTA3. 1 109.8 129. 5 118.2 132. 2 142. 2 14s. 3 141. 2

ED'IA2. 1 100. 3 121. 2 121. 2 130. 0 141.1 133. 3 130.1

Control 0 100 100 100 100 100 100 100 Water 0 91 82. 7 82.7 34. 2 82.0 as. 4 e9. 2

The textiles treated with the composition of the inven- References Cited by the Examiner y r tron can be any material which is amenable to the action 1.) UNITED STATES PATENTS of the ox1d1z1ng agents as are used in the composmon. 2 5 6 205 1 5 A The composition is preferably supplied as a dry pow- 7 1/19 1 Pperson 252 99 der and can be combined with soaps, detergents and vari- FO PA ous additives as are commonly included in laundering 721,317 4/1942 Germany compositions.

Percentages specified herein are weight percent on an anhydrous basis, unless otherwise indicated.

While various specific embodiments of the invention have been described, modifications and alterations will occur to those skilled in the art and it is intended that all such variations be secured by these Letters Patent and appended claim.

What is claimed is:

A composition consisting essentially of 85% of sodium perborate, 1% trisodium salt of nitrilotriacetic acid, and 14% of disodium phosphate for providing a pH of 7-11 in an aqueous medium.

OTHER REFERENCES JULIUS GREENWALD, Primary Examiner.

ALBERT T. MEYERS, Examiner.

M. WEINBLATT, Assistant Examiner. 

